Dryer control system



Nov. 30, 1965 D. s. LYCAN DRYER CONTROL SYSTEM 2 Sheets-Sheet 1 Filed.June 27, 62

/0-? 1/06 INVENTOR.

MAM

Nov. 30, 1965 G. LYCAN 3,220,117

DRYER CONTROL SYSTEM Filed June 27. 1962 2 Sheets-Sheet 2 INVENTOR. 170mm 4. Cyan/Y MAM United States Patent C 3,220,117 DRYER CONTROL SYSTEMDonald G. Lycan, Birmingham, MiclL, assignor to American MotorsCorporation, Detroit, Mich., a corporation of Maryland Filed June 27,1962, Ser. No. 205,700 Claims. (Cl. 3445) This invention relates tolaundry appliances applicable for the drying of clothes, fabrics and thelike and more particularly to electrical control systems used in suchappliances.

It is an object of the present invention to provide a clothes dryer withan improved electrical control system whereby the dryer may beselectively operated to produce a plurality of different clothestreating operations, with a suitable type of control being available foreach operation.

Another object of the present invention is to provide an improvedcontrol system for a clothes dryer whereby it may be selectivelyoperated to produce a plurality of different operations; a clothesdrying operation of timed length with thermostatically controlled heat,a clothes tumbling operation of timed length without heat, and a clothesdrying operation whose length is automatically varied to produce thecorrect drying period for fully drying the clothes with selectablethermostatically controlled heat.

A further object of the present invention is to provide an improvedcontrol system for a clothes dryer having a manually adjustable settingto initiate the automatically controlled drying period for fully dryingthe load placed in the dryer and whereby the manual setting isadjustable to vary the control system so as to auto matically controlthe drying period in accordance to the type and kind of fabrics thatcompose the load to be fully dried and is further adjustable to vary thecontrol system to provide the degree of dryness desired.

A still further object of the present invention is to provide a switchand circuit arrangement in a clothes dryer to insure the operation ofthe preselected automatic drying operation by energizing a timer motorat the initial start for a predetermined period to sufficiently rotatecams to insure the setting of proper timer operated switches and afterwhich the switch is automatically opened to open the circuit and stopthe timer motor.

A still further object of the present invention is to provide animproved control arrangement for a clothes dryer including dualtemperature responsive controls wherein one may be selectively placed incontrol of operation through the manual setting of the control knob.

Further objects and advantages of the present inventionwill be apparentfrom the following description, reference being had to the accompanyingdrawing, wherein a preferred form of the invention is clearly shown.

FIG. 1 is a vertical view in cross section of a clothes dryer embodyingfeatures of my invention,

FIG. 2 is a fragmentary view taken along line 22 of FIG. 1,

FIG. 3 is a schematic diagram of a control system embodying myinvention, and

FIG. 4 is a chart showing the sequence of operation of timer operatedswitches included in the system of FIG. 3.

Shown in the drawings is a clothes dryer 0' comprising in general acasing 12 within which is a drum or tumbler 14 rotatably mounted upon aplurality of rollers 16 which are grouped and arranged to provide acradle support and a drive for the drum 14. The roll ers 16 are mountedon shafts 18, 20 respectively, for rotation therewith. The shafts 18, 20are extended between spaced parallel upright walls 22, 24 and aresuitably journalled thereto. The shaft 18 is operatively connected to bedriven by an electric motor 26 through a belt drive 28. The motor 26 issupported upon a base 30 of the cabinet. The uprights 22, 24 are securedto the base 30 to extend upwardly therefrom in a spaced relation to arespective end of the drum 14.

The drum 14 comprises a cylindrical Wall 32 and end walls 34, 36. Theend walls 34, 36 are each formed with a central opening 38, 40respectively. The opening 38 is closed by a stationary closure plate 42secured to the upright wall 22. The peripheral edge of the plate 42overlaps the end wall 34 and carries a sealing member 44 which isadapted to extend to and frictionally engage the end wall 34. Thesealing member 44 extends circumferentially about the opening 38. Anopening 46 is formed in the closure plate 42 which forms an outlet for apassage 48 formed in a vertically extended duct 50. The lower end of theduct is open for entrance of air to flow upwardly for conductiontherethrough into the drum. Positioned within the passage 48 is anelectrical heating element 52.

Fixed to the upright 24 is an annular ring 56 held in spatial relationto the end wall 36 of the drum. Sealing members 58, 60 extendconcentrically about the opening 40. Each of the sealing members 58, 60are secured to the annular ring 56 to extend across for fric-' tionalengagement with the end wall 36 of the drum; Protruding through theannular ring and through the opening 40 into the drum is a neck orcollar 62. The collar 62 is aligned with an opening formed in a frontwall 66 of the casing 10 which serves as an access into the drum to beclosed by a suitable door 68. The door 68 is preferably hinged (notshown) to the front wall 66.

A vertically extended duct 70, forming a passage 72, is positionedbetween the upright wall 24 and the front wall 66. The upper end of theduct is turned to extend laterally adjacent the collar 66 and isprovided with an inlet opening 74 through which the interior of the drumis connected in open communication with the passage 72. The lower end ofthe duct 70 is turned to extend laterally, as at 76, to extend thepassage 72 into an inlet of an air moving device or blower 78. A ductcon-' nects to extend the outlet of the blower 78 exterior to the casing10. The blower 78 is operatively connected to be driven by the motor 26.

Suitable openings 82 are provided in the front wall 66 for entry of airto circulate into the casing 10 and from where it is withdrawn to passupwardly through the duct 50 wherein it is heated by contact with theheating element 52. From the duct 50 the heated air passes into therotating drum to circulate through the clothes tumbling therein toeffect their drying. The moisture laden air passes from the drum throughthe opening 74 into the passage 72. A screen filter 84 is positionedwithin the passage 72 adjacent the inlet opening 74 to trap and removelint and other like matter before the air passes into the blower 78. Theblower forces the air to pass outwardly through the conduit 80 to theatmosphere. If desired the conduit 80 may be extended by duct extensions(not shown) whereby the discharge may be at some point remote from thedryer.

The operation of the heating element 52 and the motor 26 is controlledby my new and improved control system 100 which is schematically shownin FIGS. 3 and 4. The control system 100 includes in general a timer102, a pair of cycling thermostats including switches 104, 106respectively, and a safety thermostat including switch 108.

The cycling thermostats with their switches 104, 106 are shownpositioned in the duct 80 adjacent to the outlet of the blower. However,they may be positioned in any other suitable location, as in the endplate 42 to extend into the drum so that they sense to respond to theair temperature within the drum. To de-energize the heating element 52the switch 104 is actuated when the air temperature has attainedpreferably 150 F., and the switch 106 is actuated when the airtemperature has attained preferably 170 F. The safety thermostat withswitch 108 is shown located in the air duct 50 between the heatingelement 52 and the inlet to the drum 14. The safety thermostaticallyoperated switch 108 is actuated should the selected cyclingthermostatically operated switch 104, or 106, fail to function and theair temperature in the drum begins to rise above 180 F. whereupon theswitch 108 will de-energize the heating element 52 to preventoverheating or burning of the clothes within the drum. This will be morefully set out.

The timer 102 is preferably mounted within a housing 110 on the casing12. The timer 102 comprises a pair of cams 112, 114 which are mountedupon a common shaft 116 for rotation therewith. Secured upon the shaft116 for rotation therewith is a control knob and pointer 118 to permitmanual rotation of the shaft in either a clockwise or acounter-clockwise direction to manually preset the cams. The shaft 116is operatively connected to be driven in a counterclockwise direction bya timer motor 120. The cam 112 directly engages a switch blade or reedhaving a contact 130. The periphery of the cam 112 is so arranged (notshown) that at various rotated positions it is adapted to move thecontact 130 against a contact 132, or it may effect to move to engagetogether contacts 130, 132, 134, or it may effect to move to engagetogether contacts 130, 132, 134 and 136. Each of the contacts 132, 134and 136 are also suitably mounted on a respective flexible reed, switchblade for the like to effect movement relative to each other. Preferablythe reeds are arranged to flex and carry their respective contact out ofengagement from the adjacent contact as the cam releases its pressure onthe reeds.

The cam 114 directly engages a flexible switch blade or reed having acontact 140 which contact is adapted, by rotation of the cam, to followthe cam due to its flexibility and move in one direction into anengagement with a contact 142, or be moved in an opposed direction bythe action of the cam to effect a closing of the contact 140, 144, orcontacts 140, 144 and 146 together as required.

Connected to a suitable source of electrical energy are conductors 150,152, 154. A circuit across the conductor 152 with either conductor 150or 154 provides current of 115 volts. A circuit across the conductors150, 154 provides current of a higher voltage, preferably of 230 volts.

The conductor 150 is connected to the timer contact 132. The timercontact 130 is connected by a conductor 156 to the energizing windings158 of the drive motor 26 which in turn is connected by a conductor 160to a door operated switch 162. The door switch 162 is connected to theconductor 152.

The timer contacts 134, 136 are each connected to a switch arm of thethermostatically operated switch 104. The contact 136 is connecteddirectly by a conductor 166 to the switch arm 170. The contact 134 isconnected to the switch arm 170 by a conductor 169 to a manuallyoperated switch 168 and the conductor 166.

The thermostatically operated switches 104, .106, 108 are similar inconstruction. The switches are each shown as being preferably a singlethrow double pole type. The switch 104 comprises the switch arm 170movable selectively between contacts 172, 174. The switch. 106 comprisesa switch arm movable selectively between contacts 182, 184. The switch108 comprises a switch arm 186 movable selectively between contacts 188,190. Each of the switch arms 170, 180, 186 is connected to respectivethermostats (not shown) for being biased thereby in response torespective air temperature values within the drum. Normally in theswitch 104 the switch arm 170 engages the contact 172 until the airtemperature attains a predetermined value, preferably 150 F., whereuponthe switch arm moves from contact 172 to engage upon the contact 174.For the switch 106 the switch arm normally engages the contact 182untilthe air temperature reaches a predetermined value, preferably 170 F.whereupon the arm 180 will selectively engage the opposing contact 184.In the switch 108 the normally engaged contact 188 is disengaged by theswitch arm 186 to move and engage the contact when the air temperaturereaches a predetermined value, preferably 180 F.

As the air temperature cools within the drum to fall to a predeterminedlow value each of the switch arms 170, 180, 186 will at a respectivetemperature value, preferably between 140150 F., be actuated toselectively return to normal position to re-engage its respectivecontacts 172, 182, 188.

The contact 172 of the switch 104 is connected by a conductor 200 to thecontact 182 which in turn is connected by a conductor 202 to the switcharm 186 of the safety thermostat. The contact 188 is connected by aconductor 204 to one side of a centrifugally operated switch 206positioned within the motor 26. The opposite side of the switch 206 isconnected by a conductor 208 to the heating element 52 which in turn iscon nected to the conductor 154.

One terminal of the timer motor 120 is connected to the power sourcethrough a conductor 153, door switch 162 to the conductor 152. The otherterminal of the timer motor is connected by a conductor 212 to thecontact 142, and by a conductor 214 to the contact 174 of thethermostatic switch 104. The respective switch contacts 174, 184 and 190are connected together in series circuit by a conductor 216.

The contact 130 is connected by a conductor 218 to the contact 140. Thecontact 144 is connected by a conductor 220 to the switch arm 180 of thethermostatic switch 106. The contact 146 is connected by a conductor 222to the contact 142.

Associated with the contact knob and pointer 118 of the timer 102 is astationary dial 230. The face of the dial 230 is marked, or divided intosections 232, 234, 236. Rotating the knob so that the pointer is stoppedin either the section 232 or 234 sets the control system to provide atemperature modified clothes drying operation which automaticallydetermines the drying period to fully dry the clothes. The section 232,marked W W, is preferably for the drying of clothes and fabrics whichare generally known as Wash-Wear, that is, the fabrics are of syntheticmaterial having the characteristics of absorbing little or no moistureso that to dry requires chiefly the evaporation of the surface moisturetherefrom as opposed to fabrics of organic material, such as cotton orwool, which absorb moisture. For drying the latter fabrics the knob 118is rotated with its pointed set within the section 234. The section 234(noted as Regular in FIG. 4) is subdivided into preferably threesubsections marked as L, N and H. The subsections permit the user tovary the automatically determined drying period to correspond to themoisture absorbing qualities of the articles composing the load. Theposition marked L is for a load wherein the articles composing the loadare of thin or delicate fabrics as opposed to the other extreme sectionmarked H which is designated for a load composed of heavy moistureabsorbing articles such as hand rugs, bedspreads and the like.

In each of the sections 232, 234 the user is further permitted to adjustthe control system to a finer setting to provide for the individuals owndegree of dryness requirement. That is, each individual has a personalrequirement as to the degree of dryness that is suitable for folding andstoring, or a dryness suitable for ironing and the like. In eachrequirement some percentage of natural moisture retention is desired inthe clothes as opposed to a so called bone dry condition which is foundto be undesirable as the fabric is then without its natural moisture andthis makes the fabric feel harsh to the touch, and brittle. Further, itis also necessary to adjust the control system for garments that haveheavy seams, lapped or folded over sewed sections that dry slower. Thecontrol system can be varied to provide the degree of dryness requiredby adjusting the starting setting through the positioning of the pointerin the selected section 232 or 234. When the pointer is set midway inthe section 232, or midway in either of the subsections L, N or H insection 234, an average degree of dryness is had for the respectiveload, but if the setting is varied towards either extreme in therespective section a corresponding change is had in the degree ofdryness. The percentage of natural moisture retained in the garmentswill proportionally decrease as the starting setting is advanced in theselected section towards the extreme end furthest from the off position.

A rotation of the knob and pointer 118 for a setting within the section236 provides a timed drying period of a timed length as preselected. Theduration or length being in accordance to the graduated setting to whichthe pointer is set, each graduation provides a respective preselectabletime duration.

Rotating and setting the pointer 118 into any sector on the dial 230rotates and positions the cams 112, 114 to preset respective contactswhich are graphically shown in FIG. 4. The period of interengagement ofthe contacts during the operation of the control system is representedby cross hatching and will be more fully explained hereinafter.

Setting the knob and pointer 118 into any portion of the section 232correspondingly rotates and positions the cams 112, 114 to actuate thefollowing respective contacts and close the following respectivecircuits. The cam 112 closes the contact 130 upon the contact 132 andthereby closing a circuit to energize the drive motor 26. The cam 114closes the contact 140 upon the contact 144 to select the thermostaticswitch 106 to control the energization of the heating element 52. Themotor energizing circuit is as follows: the conductor 150, the closedcontacts 130, 132, the conductor 156, motor windings 158 of the motor26, the conductor 160, the closed door operated switch 162 and theconductor 152. The circuit energizing the heating element is as follows:the conductor 150, closed contacts 132, 130, conductor 218, the closedcontacts 140, 144 conductor 220, switch arm 180 to contact 182 of thecycling thermostatic switch 106, conductor 202, switch arm 186 tocontact 188 of the safety thermostatic switch 108, conductor 204, theclosed centrifugal operated switch 206 within the motor 26, conductor208, the heating element 52 and the conductor 154. The followingautomatic drying action is initiated.

The heated air enters the rotating drum to circulate about and throughthe tumbling wet articles or clothes, and the moisture laden air is thenWithdrawn from the drum by the blower 78 to be passed to the atmosphere.A portion of the heated air circulating about the tumbling clothes isapplied to raise the temperature of the clothes and a portion of theheated air will tend to vaporize the moisture present on and in theclothes. The effect of the latent heat to vaporize the moisture acts toreduce the temperature of the clothes. Eventually a balanced conditionis reached between the increase in sensible heat and the cooling effectof vaporization to temporarily stop the rise in air temperature Withinthe drum so that for a period thereafter the clothes will continue todry at a constant temperature. The length of this period and thetemperature value at which the drying for this period occurs will ofcourse vary for different loads being dependent upon the quantity ofarticles, the heat input, the air flow and the wetness of the articles.As the drying period continues the surface moisture is reduced which inturn reduces the cooling effect due to vaporization. This results in arapid increase in the temperature of the clothes with a resultantincrease in the exhaust air until it reaches a temperature value toeffect actuation of the switch 106. In the present instant the switch106 is preferably actuated when the air temperature reaches. 170 F.whereupon the switch arm 180 disengages from the contact 182 todeenergize the heating element 52 and is biased to engage upon thecontact 184 to energize the timer motor through a circuit as follows:conductors 150, closed contacts 132, 130, conductor 218, closed contacts140, 144, the conductor 220, the switch arm 180 to contact 184, theconductors 216, 214, the timer motor and the conductor 153 through theclosed door switch 162 to the conductor 152. The operation of the timermotor rotates the cams 112, 114.

It is preferred in this drying operation, section 232, that after thetimer motor has been energized a short period that it rotate the cam 114to permit the contact 140 to bias away from the contact 144 and engageupon the contact 142 before there is a sufficient cool down tothermostatically effect an actuation of the switch 106 to reclose theheater contact. In some instances there may be a rapid cool down inwhich case the switch 106 will be actuated to re-energize the heatingelement a second time and de-energize the timer motor. Normally thetimer motor on its first run will fully rotate the cam 114 to bias thecontact 140 away from the contact 144 and upon 142. This will change thetimer motor circuit to be as follows: conductor 150, closed contact 132,130, conductor 218, closed contacts 140, 142, conductor 212, timer motor120 and conductors 153, 152 through the closed door switch 162. Thislatter circuit will insure that the timer motor will rotate the cams tofirst effect a cool down period wherein the drive motor 26 continuesrotating the drum and to drive the blower to circulate unheated airthrough the tumbling clothes. A predetermined period thereafter the cams112, 114 have been rotated to permit contact to separate from contact132 to stop the motor 26, and to be followed by the contact separatingfrom the contact 142 whereupon the timer motor is stopped with the camshaving been rotated to effect separation of all the contacts and theopening of all of the circuits. The pointer 118 will have been rotatedand halted in the stop section 240 on the dial.

In the above described drying operation, preferably adapted forWash-Wear fabrics, it is desirable that the fabrics be dried in highheat with preferably only a single energizing period for the heatingelement as the moisture is mostly surface moisture which when evaporatedthe fabric becomes fully dried. In the automatic drying cycle asdescribed above once the air temperature attains the predetermined highvalue the surface moisture on Wash- Wear fabrics is generally completelyevaporated. However other fabrics that absorb moisture, as previouslyexplained, require low heat with successive stages of heater on to bothevaporate the surface moisture and drive out the absorbed moisture. Forthis latter type of fabric load the pointer 118 is set within thesection 234 on the dial 230.

In section 234 whether the pointer is set for L, N or H the automaticoperation and the switch settings are the same, the variance is in thetimed length of the drying operation, that is, the period of operationfor the timer motor. This will be more fully set out hereinafter.

Assume the pointer 118 is set in section 234 in the subsection marked asN on the dial. The cams 112, 114 are manually preset so that the cam 112actuates to bias or close together the contacts 130, 132, 134 and 136.The cam 114 actuates no contacts at this time. The closed contacts 130,132 close the same identical circuit to energize the motor 26 asdescribed above when the pointer 118 was set in section 232. Through thecontact 136 there is closed a circuit to energize the heating element 52under control of the cycling thermostatic switch 104 as follows:conductor 150, closed contacts 132, 134, 136, conductor 166, switch arm170 to contact 172 of the cycling thermostatic switch 104, conductors200, 202, switch arm 186 to contact 188 of the safety thermostaticswitch 108, conductor 204, closed centrifugally operated switch 206,conductor 208, the heating element 52 and the conductor 154.

The heated air will circulate through the tumbling clothes and theinitial drying period will be as previously explained above when theknob was set in the section 232. A portion of the heat will be appliedto raise the temperature of the clothes and a portion to vaporize themoisture on and in the clothes until eventually a balance is reachedbetween the increase in sensible heat and the cooling effect ofvaporization so that for a period thereafter the clothes will be driedat a constant temperature value. As the surface moisture decreases thereis an increase in the tem perature of the clothes with a resultantincrease in the exhaust air to influence the actuating of the switch arm170 of the thermostatic switch 104 when the air temperature attainspreferably 150 F. The movement of the switch arm 170 from contact 172de-energizes the heating element 52 and upon engaging the contact 174energizes the timer motor 120 through the conductors 214, 153 and 152through the closed door switch 162.

The energized timer motor will operate to rotate the cams 112, 114 in acounter-clockwise direction until the air temperature drops below apredetermined value whereupon the switch 104 will be thermostaticallyactuated to bias the switch arm back to the contact 172 to re-energizethe heating element and de-energize the timer motor. Meanwhile the drivemotor 26 will continue to run uninterrupta-bly to tumble the clothes andcirculate the heated or unheated air. This cycling will continue untilthe total timers on time is sufficient to advance the cams to the cooldown section and thereafter terminate the drying cycle. In theprogressive drying of the clothes each heater on will be shorter induration, and each successive heater off will be longer. The timer motorwill therefore be on for longer periods as the clothes become dryer.This results in a drying cycle that is partially self-compensating forthe variations in the moisture content of each load. By manually settingthe pointer in a proper portion of the section 130 in accordance to theload or type of load placed in the dryer the timer cams are preset toprovide for the necessary longer or shorter period of drying time toprovide for the natural moisture retention as desired by the user.

The cycling air heatingperiod terminates when the cam 112 has beenrotated to effect a separation of the contacts 134, 136. At this timethe contact 130 remains in engagement with the contact 132 to continueenergizing the motor 26 for a predetermined longer period. Just prior tothe separation of contacts 134, 136 the cam 114 has rotated to effectthe closing of contact 140 upon 142 to close an alternate circuit toenergize the timer motor for a predetermined concluding cool downoperational period after which period all operations will cease. Thiscircuit follows from conductor 152, closed contacts 132, 130, conductor218, closed contacts 140, 142, conductor 212, timer motor 120,conductors 153, 152 through the closed door switch 162. During this cooldown operational period the clothes are tumbled and cooled bycirculating unheated air therethrough. At the end of this period thecams 112 and 114 will effect a separation of the contacts 130, 132 andthe contacts 140, 142 respectively. This concludes the automatic dryingperiod with all circuits being opened and the knob being rotated to haltin the stop section 242 on the dial 230.

It is to be noted that in the above described automatic drying operationthe timer motor is first initiated in operation by the cyclingthermostat after a maximum air temperature within the drum has beenattained. It has been found that by this arrangement the operator, whendesiring the full or maximum drying period in either of the twoselectable automatic drying operations, may so manually rotate and stopthe pointer 118 whereby the cams are at the marginal setting point forinitiating actuation of the switches or contacts without fully actuatingall of the necessary contacts. Particularly can such a condition occurwhere there is an allowance permitting a slight play or movement betweenthe cam and shaft, and the manual rotation for setting the cam is beingmade counter-clockwise. As the operator sets and momentarily holds thepointer at the marginal starting point the cam 112 will hold close thecontacts 132, to start the motor 26 and thereby effect a closing of thecentrifugal switch 206. As soon as the pointer is released by theoperator the cam may backlash to effect a re-opening of the contacts132, 130 with the following results for the automatic drying operations.

Assume the preselection is for the Wash-Wear operation, a setting in thesection 232. The initial period of operation of the motor 26, before thecontacts 130, 132 reopen, will close the switch 206 and with the closedpreset contacts 140, 144 will form a circuit connecting the heatingelement 52 and the drive motor 26 in series circuit through thethermostatic switches 106, 108 across the conductors 152, 154. Thiscircuit will allow the motor 26 to continue operating, even thoughcontacts 130, 132 are separated, and the heater to functioninefficiently. As the heating element is in a low voltage circuit itwill not provide sufficient heat to effect thermostatic action. Thisineffective operation would continue until noticed by the operator whothen would be required to manually advance the timer by further counterclockwise rotation of the knob.

The heating element 52 is of the high voltage type hav ing a lowresistance, preferably 10 ohms. Because of the low voltage drop across aheating element of this type the motor 26 will operate in seriesconnection therewith as explained above. Further, it will also permitthe operation of the timer motor therewith, as will be explainedhereinafter.

To automatically correct and automatically advance the timer when theabove described condition occurs the contacts 140, 144 are closed downupon the contact 146 by the cam 114 prior to the action of the cam 112as to its respective contacts (see FIG. 4). The closed contacts 140,144, 146 preset a circuit to the timer motor 120 so that should theabove backlash occur the timer motor will also be simultaneouslyenergized in a parallel circuit with the drive motor. The timer motorcircuit follows from conductor 154, heating element 52, switch 108,conductor 20.2, switch 106, conductor 220, closed contacts 144, 146,conductor 212, timer motor 120 and conductors 153, 152. After a shortinterval of timer motor operation the cam 112 will be advanced to effecta reclosure of contacts 130, 132 and thereafter the cam 114 will havebeen advanced to effect a separation of the contacts 146,

9 144 to halt operation of the timer motor. Thereafter the timer motoris alternately energized with the heating element by action of thethermostatically operated switch 106.

Assume the preselection is for the regular automatic operation (see FIG.4), a setting in section 234 on the dial. The contacts 140, 144, 146 areprovided to be preset closed prior to the actuation of the contacts bythe cam 112 when the cams are rotated counterclockwise for a presetting.Should a backlash occur to reopen the closed contacts 130, 132, 134 thesame circuit would be had as explained above for energizing the timermotor simultaneously with the series energized motor 26 and heatingelement 52. However, the cam 112 may only close contacts 130, 132 butfail as to contact 134 in which case the motor circuit will be closedsimultaneously with the timer motor circuit. The timer motor circuithere would follow from conductor 150, across closed contacts 132, 130,conductor 218, closed contacts 140, 144, 146, conductors 222, 212, thetimer motor 120 and conductors 153, 152. After a predetermined period oftimer operation the contacts 140, 144, 146 are separated by theadvancement of the cam 114 from each other (see FIG. 4). Thisarrangement permits the timer motor operation only for a duration toinsure that the cams have been rotatably advanced and preset to properlyactuate and close the required contacts to provide the required circuitsfor the preselected dryer operation.

Rotatably setting the pointer 118 within the section 236 of the dialinitiates a straight time controlled operation for either heated airdrying or unheated air tumbling operation. The length or duration of theperiod being that as selected by the user in setting the pointer to atime designated graduation. The timer motor will be energized from themoment the pointer is set within the section 236 and will continue torun uninterruptingly for the pre selected time period after which alloperations are halted and all circuits opened. The thermostatic switch104 cycles the heating element 52 to provide for heated air circulation.To provide for heated air circulation the switch 168 must be manuallyclosed. Manually opening the switch 168 provides an unheated tumbling orfiuffing operation.

With the pointer rotated and set in the section 236 and the manuallyclosing of the switch 168 to provide a heated air drying operation thefollowing switches and circuits are closed. The manual presetting of thecam 112 actuates and closes the contacts 130, 132 and 134 together. Theclosed contacts 130, 132 close an already described circuit to energizethe motor 26 to operatively rotate the drum and drive the blower. Theheaing element 52 is energized through a circuit as follows: conductor150, closed contacts 132, 134, conductor 169, closed switch 168, acrossswitch arm 170 and contact 172 of the cycling thermostatic switch 104,conductors 200, 202, the safety thermostatic switch 108, conductor 204,the closed centrifugtally operated switch 206, the conductor 208, theheating element 52 and the conductor 154. The movement of the switch arm170 of the thermostatic switch 104 from contact 172 to 174 merelyinterrupts the circuit to the heating elements. The timer motor circuitis also closed by the manual setting of the cam 114 biasing the contact140 upon the contact 142 which completes the circuit from the conductor150, closed contacts 132, 130, conductor 218, closed contacts 140, 142,conductor 212, the timer motor 120 and conductor 152. The rotation ofthe cams by the timer motor determines the drying period, and as the cam112 approaches the terminable end for the drying period the cam 112 willeffect a separation of the contact 134 from 132 to open the circuit tothe heating element 52 to terminate the air heating period. For a periodthereafter the clothes will be tumbled with unheated air circulatedtherethrough to effect a cooling of the clothes. Following this periodthe cam 112 will effect the separation of the contacts 130, 132, and thecam 114 10 will simultaneously effect the separation of the contacts140, 144 to stop the drive motor 26 and the timer motor respectively.The pointer of the knob 118 having been rotated by the timer motor willbe stopped in the adjacent off position 244 on the dial 230.

To provide for a fluffing operation the pointer 118 is set in thesection 236 to a graduation for a preselected time period as desired.The switch 168 is manually operated to open position. The timer motor isenergized for continuous operation by the closing of the contacts 140,144, and the drive motor is energized by the closure of the contacts130, 132 in the same manner as described above for the straight timeoperational drying period. The operation is likewise similar except thatwith the switch 166 in open position the air heating element 52 is notenergized and the clothes are tumbled with unheated air circulatedtherethrough for a preselected period.

The door operated switch 162 is mounted to the cabinet (not shown) to beactuated by the opening and closing of the door 68. The opening of thedoor 68 actuates the switch to an open position which prevents thestarting of any of the drying operations described above, or will duringthe drying period break the motor circuit so as to deenergize and stopthe motor 26. Stopping the motor 26 will actuate the internal switch 206to open so as to deenergize the heating element 52. Reclosing the doorrecloses the switch 162 to restart the running of the motor 26 and itsoperation will through centrifugal action reclose the switch 206 tore-energize the heating element. The timer motor operation is alsoaffected by the door switch 162. For example, in the automatic dryingoperation, sections 232, 234 on the dial, should the door he opened whenthe timer motor 120 is running, it will stop running while the door isheld open. Upon reclosing of the door the cycling thermostat may callfor heat whereupon the timer motor will remain de-energized until thethermostat is again satisfied before re-energizing the timer motor.Reclosing the door will restart the circulating and tumbling operation,and any cool down will automatically be compensated for by returning theair temperature to the desired value which is a balance between theincrease in sensible heat and the cooling effect of vaporization withinthe dryer before the timer motor will be re-energized. Interrupting theair heating cycle period by the opening of the door 68 will continue theair heating cycle upon the reclosing of the door irrespective whetherthe drying operation was initiated in section 232, 234 or 236.

From the above it will be noted that there is provided a control systemfor a clothes dryer where the user is permitted a choice of methods forthe drying of clothes by either fully drying automatically, or drying toa degree of dryness by a predetermined selection of the drying period.Further, the user may adjust the control system to automaticallycompensate for the quantity, type and kind of fabrics and clothing thatare to be fully dried automatically. Also there is provided a controlarrangement to insure the starting and operation of the automatic dryingoperation when the control is manually set at the marginal startingpoint for the maximum drying ,period desired for slow drying articles.

Although only a preferred form of the invention has been illustrated,and that form described in detail, it will be apparent to those skilledin the art that various modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

I claim:

1. In a clothes dryer, clothes tumbling means, air moving means forcirculating air through said clothes tumbling means, a drive motor fordriving said clothes tumbling means and said air moving means, a heatingelement for heating the air circulating through said tumbling means, acontrol system including a timer and a motor for driving said timer forcontrolling said drive 1 1 motor and said heating element to produceselectively; a plurality of temperature modified clothes dryingoperations wherein said timer operates only after the dryer temperaturerises to a predetermined high temperature, and a timed clothes dryingoperation, a pair of thermostatically operated switches each havingheater contacts and timer contacts and being adapted to alternately opensaid heater contacts and close said timer contacts, the first of saidthermostatically operated switch being re sponsive to a predeterminedhigher air temperature than the second switch to open its respectiveheater contact and close its respective timer contact, and each of saidfirst and second thermostatically operated switches Opening said timercontact and reclosing said heater contact when said air temperaturefalls to a respective predetermined low temperature, said control systemincluding switch means comprising a first group of first, second andthird contacts being adapted to be actuated for selective interengagement by said timer, and a second group of fourth, fifth and sixthcontacts with said fourth contact movable by said timer to selectivelyengage said fifth and sixth contacts; a first circuit for energizingsaid drive motor through closing said first upon said second contacts, asecond circuit energizing said heating element being connected'with saidheater contact of said second thermostatically operated switch and theclosing of said first group of contacts, a third circuit energizing saidheating element being connected with said heater contact of said firstthermostatically operated switch and the closing of said fourth uponsaid fifth contact, a fourth circuit energizing said timer motor beingconnected with said fourth contact closing upon said sixth contact, acircuit interconnecting said timer contacts of said first and secondthermostatically operated switches and said timer motor, said timerhaving different presettable operating ranges and operating saidcontacts to produce selectively a first temperature modified clothesdrying operation to provide said first and third circuits, a secondtemperature modified clothes drying operation to provide said first andsecond circuits, a timed drying operation to provide said first, secondand fourth circuits, said presettable operating ranges of said timerhaving means arranged to operatively control said second and said thirdcircuits wherein the selection of one of said circuits being providedwith a longer period for energization of the heating element than theselection of the other circuit, and a rotatable knob for adjusting saidtimer to adjust said control system to produce the desired one of saidoperations.

2. In a clothes dryer, clothes tumbling means, air moving means forcirculating air through said clothes tumbling means, a drive motor fordriving said clothes tumbling means and said air moving means, a heatingelement for heating the air circulating through said tumbling means, acontrol system including a timer and a motor for driving said timer forcontrolling said drive motor and said heating element to produceselectively; a plurality of temperature modified clothes dryingoperations wherein said timer operates only after the dryer temperaturerises to a predetermined high temperature, and a timed clothes dryingoperation, a pair of thermostatically operated switches each havingheater contacts and timer contacts and being adapted to alternately opensaid heater contacts and closing said timer contacts, the first of saidthermostatically operated switch being responsive to apredeterminedhigher air temperature than the second switch to open its respectiveheater contact and close its respective timer contact, and each of saidfirst and second thermostatically operated switches opening said timercontact and reclosing said heater contact when said air temperaturefalls to respective predtermined low temperatures, said control systemincluding switch means comprising a first group of first, second andthird contacts being adapted to be actuated for selecfiveinterengagement by said timer, and a second group of fourth, fifth andsixth contacts with said fourth contact movable by said timer toselectively engage said fifth and sixth contact; a switch manuallyoperable between open and closed position, a first circuit forenergizing said drive motor through. closing said first upon said secondcontacts, a second circuit energizing said heating element beingconnected with said heater contact of said second thermostatic switch,said switch manually set in closed position and through the closing ofsaid first group of contacts, a third circuit energizing said heatingelement being connected with said heater contact of said firstthermostatically operated switch and through the closing of said fourthupon said fifth contact, a fourth circuit energizing said timer motorbeing connected with said fourth contact being closed upon said sixthcontact, a circuit interconnecting said timer contacts of said first andsecond thermostatically operated switches and said timer motor, saidtimer having different presettable operating ranges and operating saidcontacts to produce selectively a first temperature modified clothesdrying operation to provide said first and third circuits, a secondtemperature modified clothes drying operation to provide first andsecond circuits wherein said switch is preset in closed position, atimed drying operation or a timed tumbling operation without heat toprovide said first, second and fourth circuits wherein said manuallyoperable switch is preset in closed position for a timed dryingoperation and preset in open position for timed tumbling operation, saidpresettable operating ranges of said timer having means arranged tooperatively control said second and said third circuits wherein theselection of one of said circuits being provided with a longer periodfor energization of the heating element than the selection of the othercircuit, and a rotatable knob for adjusting said timer to adjust saidcontrol system to produce the desired one of said operations.

3. In a clothes dryer, clothes tumbling means, air moving means forcirculating air through said clothes tumbling means, a drive motor fordriving said clothes tumbling means and said air moving means, a heatingelement for heating the air circulating through said tumbling means, acontrol system including a timer and a motor for driving said timer forcontrolling said drive motor and said heating element to produceselectively; a plurality of temperature modified clothes dryingoperations wherein said timer operates only after the dryer temperaturerises to predetermined high temperatures, a timed clothes dryingoperation, and a timed clothes tumbling operation without heat, a pairof thermostatically operated switches connected in series and eachhaving heater contacts and timer contacts and being adapted toalternately open said heater contacts and close said timer contacts, thefirst of said thermostatically operated switch being responsive topredetermined higher air temperatures than said second switch to openits respective heater contact and close its respectively timer contact,and each-of said first and second thermostatically operated switchesopening said timer contact and reclosing said heater contact responsiveto respective predetermined low temperatures, said control systemincluding switch means comprising a first group of first, second, thirdand fourth contacts being adapted to be actuated for selectiveinterengagement by said timer, and a second group of fifth, sixth andseventh contacts with said fifth contact movable by said timer toselectively engage said sixth and seventh contact; a first circuit forenergizing said drive motor being connected through closing said firstupon said second contacts, a second circuit energizing said heatingelement beingconnected to said heater contact of said secondthermostatically operated switch and through the closing of said firstgroup of four contacts, a third circuit energizing said heating elementbeing connected with said heater contact of said first thermostaticallyoperated switch and through the closing of said fifth upon said sixthcontact, a fourth circuit energizing said timer motor through closing ofsaid fifth upon said seventh contact, a circuit interconnecting saidtimer contacts of said first and second thermostatically operatedswitches and said timer motor, a switch manually operated between openand closed position, said switch being connected in series circuit withsaid third contact and said heater contact of said secondthermostatically operated switch, a fifth circuit energizing saidheating element being connected with said heater contact of said secondthermostatically operated switch through the interengagement of saidfirst, second and third contacts and said manually operated switch inclosed position, said timer having different presettable operatingranges and operating said contacts to produce selectively a firsttemperature modified clothes drying operation to provide said first andthird circuits, a second temperature modified clothes drying operationto provide said first and second circuits, a timed drying operation toprovide said first, second, and fourth circuits, a timed tumblingoperation without heat to provide said first, fourth and fifth circuitswherein said manually operated switch is in open position, saidpresettable operating ranges of said timer having means arranged tooperatively control said second and third circuits wherein the selectionof one of said circuits being provided with a longer period forenergization of the heating element than the selection of the othercircuit, and a rotatable knob for adjusting said timer to adjust saidcontrol system to produce the desired one of said operations.

4. In a clothes dryer, clothes tumbling means, air moving means forcirculating air through said clothes tumbling means, a drive motor fordriving said clothes tumbling means and said air moving means, a heatingelement for heating the air circulating through said tumbling means, acontrol system including a timer and a motor for driving said timer forcontrolling said drive motor and said heating element to produceselectively: a plurality of temperature modified clothes dryingoperations wherein said timer operates only after the dryer temperaturerises to a predetermined high temperature, and a timed clothes dryingoperation; a plurality of thermostatically operated switches connectedin series and each having heater contacts and timer contacts and beingadapted to alternately open said heater contacts and close said timercontacts upon a predetermined high air temperature and opening saidtimer contacts and reclosing said heater contacts when the airtemperature falls to a predetermined low temperature, the first of saidthermostatically operated switches being responsive to a predeterminedhigher air temperature than a second thermostatically operated switchresponsive to a predetermined higher air temperature than a thirdthermostatically operated switch to open its respective heater contactand closing its respective timer contact, said control system includingswitch means comprising a first, second and third contact being adaptedto be actuated for selective interengagement by said timer, and a secondgroup of fourth, fifth and sixth contacts with said fourth movable bysaid timer to selectively engage said fifth and sixth contacts; a firstcircuit for energizing said drive motor through closing said first uponsaid second contacts, a second circuit energizing said heating elementbeing connected with said heater contacts of said first and thirdthermostatically operated switch in series and through the closing ofsaid first group of contacts, a third circuit energizing said heatingelement being connected with said heater contact of said first andsecond thermostatically operated switch in series and through theclosing of said fourth upon said fifth contact, a fourth circuitenergizing said timer motor through closing of said fifth upon saidseventh contact, a circuit interconnecting said timer contacts of eachof said thermostatically operated switch and said timer motor, saidtimer having different presettable operating ranges and operating saidcontacts to produce selectively a first temperature modified clothesdrying operation to provide said first and third circuits, a secondtemperature modified clothes drying operation to provide said first andsecond circuits, a timed drying operation to provide said first, secondand fourth circuits, said presettable operating ranges of said timerhaving means arranged to operatively control said second and thirdcircuits wherein the selection of one of said circuits being providedwith a longer period for energization of the heating element than theselection of the other circuit, and a rotatable knob for adjusting saidtimer to adjust said control system to produce the desired one of saidoperations.

5. In a clothes dryer, clothes tumbling means, air moving means forcirculating air through said clothes tumbling means, a drive motor fordriving said clothes tumbling means and said air moving means, a heatingelement for heating the air circulating through said tumbling means, acontrol system including a timer and a motor for driving said timer forcontrolling said drive motor and said heating element to produceselectively; a plurality of temperature modified clothes dryingoperations wherein said timer operates only after the dryer temperaturerises to a predetermined high temperature, and a timed clothes dryingoperation; a plurality of thermostatically operated switches connectedin series and each having heater contacts and timer contacts and beingadapted to alternately open said heater contacts and close said timercontacts upon a predetermined high air temperature and opening saidtimer contacts and reclosing said heater contacts when the airtemperature falls to a predetermined low temperature, the first of saidthermostatically operated switches being responsive to a predeterminedhigher air temperature than a second thermostatically operated switch,and said second thermostatically operated switch being responsive to apredetermined higher air temperature than a third thermostaticallyoperated switch to open its respective heater contact and closing itsrespective timer contact, said control system including switch meanscomprising a first group of first, second, third and fourth contactsbeing adapted to be actuated for selective interengagement by saidtimer, and a second group of fifth, sixth and seventh contacts with saidfifth contact movable by said timer to selectively engage said sixth andseventh contacts; a first circuit for energizing said drive motor beingconnected with closing said first upon said second contacts, a secondcircuit energizing said heating element being connected with said heatercontacts of said first and third thermostatically operated switch inseries and through the closing of said first group of contacts, a thirdcircuit energizing said heating element being connected with said heatercontact of said first and second thermostatically operated switch inseries and through the closing of said fifth upon said sixth contact, afourth circuit energizing said timer motor through closing of said fifthupon said seventh contact, a circuit interconnecting said timer contactsof each of said thermostatically operated switches and said timer motor,a switch manually operated between open and closed position, said switchbeing in series circuit interconnecting said heater contact of saidsecond thermostatic switch and third con- 15 and fourthcircuits, a timedtumbling operation without heat to provide said first, fourth and fifthcircuit wherein said manually operated switch is in open position, saidpresettable operating ranges of said timer having means arranged tooperatively control said second and third circuits wherein the selectionof one of said circuits being provided with a longer period forenergization of the heating element than the selection of the othercircuit, and a rotatable knob for adjusting said timer to adjust saidReferences Cited by the Examiner UNITED STATES PATENTS Engel 34-45Hughes 34'45 Raley 34-45 Gray 34-45 Morey 34-45 Berenbaum 34,-45

control system to produce the desired one of said opera- 10 WILLIAMPrimary Examiner- NORMAN YUDKOFF, Examiner.

tions.

1. IN A CLOTHES DRYER, CLOTHES TUMBLING MEANS, AIR MOVING MEANS FORCIRCULATING AIR THROUGH SAID CLOTHES TUMBLING MEANS, A DRIVE MOTOR FORDRIVING SAID CLOTHES TUMBLING MEANS AND SAID AIR MOVING MEANS, A HEATINGELEMENT FOR HEATING THE AIR CIRCULATING THROUGH SAID TUMBLING MEANS, ACONTROL SYSTEM INCLUDING A TIMER AND A MOTOR FOR DRIVING SAID TIMER FORCONTROLLING SAID DRIVE MOTOR AND SAID HEATING ELEMENT TO PRODUCESELECTIVELY; A PLURALITY OF TEMPERATURE MODIFIED CLOTHES DRYINGOPERATIONS WHEREIN SAID TIMER OPERATES ONLY AFTER THE DRYER TEMPERATURERISES TO A PREDETERMINED HIGH TEMPERATURE, AND A TIMED CLOTHES DRYINGOPERATION, A PAIR OF THERMOSTATICALLY OPERATED SWITCHES EACH HAVINGHEATER CONTACTS AND TIMER CONTACTS AND BEING ADAPTED TO ALTERNATELY OPENSAID HEATER CONTACTS AND CLOSE SAID TIMER CONTACTS, THE FIRST OF SAIDTHERMOSTATICALLY OPERATED SWITCH BEING RESPONSIVE TO A PREDETERMINEDHIGHER AIR TEMPERATURE THAN THE SECOND SWITCH TO OPEN ITS RESPECTIVEHEATER CONTACT AND CLOSE ITS RESPECTIVE TIMER CONTACT, AND EACH OF SAIDFIRST AND SECOND THERMOSTATICALLY OPERATED SWITCHES OPENING SAID TIMERCONTACT AND RECLOSING SAID HEATER CONTACT WHEN SAID AIR TEMPERATUREFALLS TO A RESPECTIVE PREDETERMINED LOW TEMPERATURE, SAID CONTROL SYSTEMINCLUDING SWITCH MEANS COMPRISING A FIRST GROUP OF FIRST, SECOND ANDTHIRD CONTACTS BEING ADAPTED TO BE ACTUATED FOR SELECTIVEINTERENGAGEMENT BY SAID TIMER, AND A SECOND GROUP OF FOURTH, FIFTH ANDSIXTH CONTACTS WITH SAID FOURTH CONTACT MOVABLE BY SAID TIMER TOSELECTIVELY ENGAGE SAID FIFTH AND SIXTH CONTACTS; A FIRST CIRCUIT FORENERGIZING SAID DRIVE MOTOR THROUGH CLOSING SAID FIRST UPON SAID SECONDCONTACTS, A SECOND CIRCUIT ENERGIZING SAID HEATING ELEMENT BEINGCONNECTED WITH SAID HEATER CONTACT OF SAID SECOND THERMOSTATICALLYOPERATED SWITCH AND THE CLOSING OF SAID FIRST GROUP OF CONTACTS, A THIRDCIRCUIT ENERGIZING SAID HEATING ELEMENT BEING CONNECTED WITH SAID HEATERCONTACT OF SAID FIRST THERMOSTATICALLY OPERATED SWITCH AND